package com.da.mybatis.config;

import java.lang.reflect.Method;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import cn.hutool.json.JSONObject;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.da.mybatis.annotation.NeedToken;
import com.da.mybatis.model.User;
import com.da.mybatis.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

/**
 * 登录拦截器
 */
public class AuthenticationInterceptor implements HandlerInterceptor {
    @Autowired
    UserService userService;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
                             Object object) throws Exception {
        String token = request.getHeader("token");// 从 http 请求头中取出 token
        // 如果不是映射到方法直接通过
        if (!(object instanceof HandlerMethod)) {
            return true;
        }
        HandlerMethod handlerMethod = (HandlerMethod)object;
        Method method = handlerMethod.getMethod();
        //检查是否有passtoken注释，有则跳过认证
        //if (method.isAnnotationPresent(PassToken.class)) {
        //    PassToken passToken = method.getAnnotation(PassToken.class);
        //    if (passToken.required()) {
        //        return true;
        //    }
        //}
        //检查有没有需要用户权限的注解
        if (method.isAnnotationPresent(NeedToken.class)) {
            JSONObject json = new JSONObject();
            NeedToken needToken = method.getAnnotation(NeedToken.class);
            if (needToken.required()) {
                response.reset();
                response.setCharacterEncoding("utf-8");
                response.setContentType("application/json");
                ServletOutputStream os = response.getOutputStream();
                // 执行认证
                if (token == null) {
                    json.set("message", "no token");
                    json.set("code", 500);
                    os.print(json.toString());
                    return false;
                }
                // 获取 token 中的 user id
                String userId;
                try {
                    userId = JWT.decode(token).getAudience().get(0);
                } catch (JWTDecodeException j) {
                    json.set("message", "token invalid");
                    json.set("code", 500);
                    os.print(json.toString());
                    return false;
                }
                User user = userService.getUserById(Integer.parseInt(userId));
                if (user == null) {
                    json.set("message", "account not exist");
                    json.set("code", 500);
                    os.print(json.toString());
                    return false;
                }
                // 验证 token
                JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(user.getName())).build();
                try {
                    jwtVerifier.verify(token);
                } catch (JWTVerificationException e) {
                    json.set("message", "invalid fail");
                    json.set("code", 500);
                    os.print(json.toString());
                    return false;
                }
                return true;
            }
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse,
                           Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse,
                                Object o, Exception e) throws Exception {
    }
}